With their backs to the wall, Democrats want two things from Congress this fall: a fast break and a political bank shot — melding small-business relief with a fight over Bush-era tax cuts for the wealthy.

The pieces are set for Senate passage of a long-delayed, small-business bill promising expanded credit and $55 billion in tax breaks in the first two years. House Ways and Means Committee Chairman Sander Levin told POLITICO that despite past reservations, he’s ready to send the bill to President Barack Obama without revisions.

“The House must act,” said the Michigan Democrat. “We will not let that bill not become law.”

Amid renewed Senate sniping Monday, the path for the Bush tax cuts is less clear. But Democrats believe that standing pat in today’s political climate is more perilous than plunging ahead.

Early polls confirm this judgment: Extending the middle-class portion is popular, but even independents fear the $700 billion 10-year cost of sustaining the high-end tax breaks.

Senate Minority Leader Mitch McConnell is firm, even defiant, in his resistance. “Only in Washington could someone propose a tax hike as an antidote to a recession,” he told colleagues Monday. And the Kentucky Republican went so far as to introduce a massive tax package late Monday that would blow a huge hole in Obama’s budget plans by not only making all the Bush cuts permanent but also greatly expanding estate tax relief and that for the alternative minimum tax.

By comparison, House Republicans, who must all stand for election in November, appear more open to compromise and are wavering, as evidenced by mixed counteroffers from Minority Leader John Boehner (R-Ohio).

Instead of allowing taxes to rise on the wealthy, Boehner would extend the current rates for two more years and cover the cost by cutting domestic agencies and the State Department by $84 billion, or 18 percent below current levels.

That’s truly a return to former President George W. Bush circa late 2007. The impacts would be felt by not only education but also foreign policy, and the appropriations cut is four times what Senate Republicans have proposed thus far, giving Obama fresh fodder on the stump.

That said, not all is smooth sailing for the president.

Obama’s celebrity-hungry former budget director, Peter Orszag, undercut him on the tax break rollback in a debut New York Times column last week. And as the storm clouds gather, Senate moderates have the harried look of sodbusters longing for a safe tornado cellar.

The plan now is for Senate Democrats to take the lead with a bill preserving only the middle-class tax cuts without the high-end breaks. If this collapses for lack of 60 votes — as Republicans predict — the House could still act and potentially change the dynamics.

Boehner and former Speaker Newt Gingrich (R-Ga.) signaled Sunday that House Republicans won’t stand in the way of permanent middle-class reductions — if Boehner’s two-year extension, including the high-end rates, were to fail.

Rural Blue Dogs and suburban Democrats from wealthy districts are nervous, but House Speaker Nancy Pelosi (D-Calif.) seems ready to call Boehner’s bluff, and Tuesday night’s House Democratic Caucus will reveal how much the party is willing to gamble, even if it means touching what’s been a dangerous third rail: tax hikes.

Pollster Stan Greenberg, who will speak to the caucus, told POLITICO that a majority of independents, 53-38, support the Democrats’ tax position in his latest survey. And that taking a stand helps narrow the voter-preference gap between Democratic House candidates and Republicans, now leading on the generic ballot.

“You want to shake people. We ought to be proactive,” Greenberg said. “This is one issue where we have the high ground.”

“It’s not so one-sided that it’s 80-20, but they need every long straw they can find to move people,” agreed pollster Peter Hart.

Indeed, high unemployment and an August dip in voter confidence in the economy are crushing Democrats, and neither party is under any illusions about the political landscape at home.

Democrats still need a stopgap spending bill to keep the government operating past Oct. 1, but beyond that and the tax battle, the leadership will have a hard time keeping its members from bolting to the campaign trail.

“They are heading toward an enormous electoral defeat and must do everything to change that narrative,” said Bill McInturff of Public Opinion Strategies. “It’s not that Republicans are morons. We did everything they’re doing in 2006, and we still lost.”

The latest NBC News-Wall Street Journal survey, overseen by Hart, a Democrat, and McInturff, a Republican, is revealing.

Obama’s job approval rating has dropped to 45 percent; on economic matters, it’s still lower, at 39 percent. But the political killer is that only about one out of four voters thinks that the economy will improve in the next year.

At the same time, neither party’s message is judged very convincing by voters in the survey. Republicans fare even worse here among independents than do Democrats. Measured against the last off-year election, which in 2006 cost Republicans control of Congress, Obama is less a target than Bush was then.

Voters now split 29 percent to 27 percent when asked whether their choice for Congress signals opposition to or support for Obama. In October 2006, the same question found a much wider — 37 percent to 22 percent — division against Bush. And for all the criticism of last year’s economic recovery bill, the survey found voters evenly divided: 30 percent say it made things better, 30 percent say it made things worse and 30 percent say it’s too soon to tell.

These numbers give Democrats hope there’s still a window to get a message out before November — an almost “teachable moment” for Obama to use the tax choices to reframe the election.

The immediate goal is to energize a crucial 10 percent bloc of Obama voters, who are still sympathetic yet unlikely to turn out for House and Senate candidates.

To succeed, the president faces a two-part challenge: He must draw sharper lines so voters can choose but also show he is the pragmatic problem solver he promised to be.

So much of Obama’s agenda has been “big and bold” — the giant stimulus bill, health care and Wall Street reform — that this side of him is obscured.

Prior to the August recess, he and Democrats found a formula to protect teachers’ jobs that included practical spending cuts to pay for the cost. Yet the administration never highlighted that as a model for going forward.

The tax debate now is a second chance — and a doozy for any problem solver.

Obama likes to joke that Republicans drove the economy into a ditch and now want the keys back while he’s still trying to free the car. Left unsaid — but exposed in the revenue fight — is that the same car is also out of gas.

Thus the president got himself in trouble Friday when he suggested that revenues saved by not extending all the tax cuts could be the subject of discussions with Republicans. In fact, the full $700 billion is already baked into Obama’s deficit assumptions — as Democrats found when some suggested the $250,000 threshold for tax increases be raised to $1 million.

Anything’s possible with enough votes for waivers. But under pay-go budget rules, any adjustment would mean coming up with new revenue or spending offsets.

No conundrum is bigger than small businesses.

The Joint Tax Committee estimates that only 3 percent of small-business owners generate enough income to be hit by the higher rates; H&R Block told POLITICO that of its 1.5 million small-business clients, fewer than half a percent are affected.

But the National Federation of Independent Business said the tax change will affect 40 percent of companies with 20 to 250 workers — precisely the employers able to generate more jobs. And Republicans point to the fact that about half of the $1 trillion in net positive business income reported each year comes on returns that are at least partially subject to the higher rates.

Breaking down this data is a challenge.

Democrats say much of this income flows from hedge funds and law partnerships, some with receipts in excess of $50 million and scarcely “small.” But research by Senate Finance Committee Republicans shows that manufacturers and retail companies are indeed part of the mix, and Sen. Chuck Grassley (R-Iowa) said Obama is contradicting his own advice to resist tax hikes in a recession.

“Small business operates on cash flow,” Grassley said in an interview. “You don’t create jobs by taking money out.”

How much comes out — and whether it can be limited — is the next question.

The tax write-offs in the small-business bill are a short-term buffer for this year and next. And, like all high-end taxpayers, small-business owners would still share in the middle-class tax cuts that Obama proposes to continue.

For example, in making their case, Senate Finance Committee Republicans cite a small-business owner, married with two children, $321,200 in income and $70,300 in itemized deductions. His taxes would go up by almost $2,100, but that’s just a 4 percent increase over what the owner currently pays — largely because he still has the middle-class breaks.

“We’re for permanent tax cuts for the middle class,” said Senate Finance Committee Chairman Max Baucus (D-Mont.). “These differing viewpoints on the top rates should in no way impede our effort to provide critical tax cuts for middle-class families.”